G&L MMC-A2, Hardware Manual

Page: 33 / 192

Installation, Operation, & Maintenance
G & L Motion Control Inc. MMC Hardware Manual 25
information including power supply status, battery status, diagnostic status,
and system status.
Figure 3-8: Status Lights
3.8.1 Power Status
The green Power light (P) indicates that the power supplies internal
to the MMC are working properly. If the power light (P) does not
go on, or goes off during operation of the system, check that the
proper voltage is present at the MMC power connector. If it is, turn
off the main disconnect switch and replace the MMC.
3.8.2 Battery Status
If the green Power light (P) on the Standalone MMC Control starts
flashing, the battery must be replaced. Follow the battery
replacement procedure in
Section 4.9 on page 85 . Note that the
Standalone Digital MMC Control does not use the Power light to
report a low battery condition, but rather uses a Diagnostic light
error code (
Section 3.8.6 on page 27 ) to report this condition.
3.8.3 Scan Status
The green Scan light (S) indicates that the application program is
running. If the Scan light does not go on:
1. Check that the power light (P) is ON.
2. Check that the diagnostic light (D) is OFF.
3. Verify that there is a Ladder in the MMC’s application mem-
ory.
Whenever the scan light is out, the discrete outputs go to the OFF
state and the analog outputs are zeroed.
3.8.4 Power-up Diagnostics Status
When the system is powered up, it tests itself and reports the results
of the tests using the yellow Diagnostic light (D).
When power is applied to the MMC, the Diagnostic light comes on
briefly while its diagnostic tests are running. After the power-up
S P D